#include <stdio.h> int main() { double num1, num2, result; char op; while (1) { printf("nEnter two numbers (or press q to quit): "); // Check if user wants to quit if (scanf("%lf %lf", &num1, &num2) != 2) { scanf(" %c", &op); if (op == 'q' || op == 'Q') { printf("Program terminated.n"); break; } else { printf("Invalid input.n"); // Clear input buffer while (getchar() != 'n'); continue; } } while (1) { printf("Enter operator (+, -, *, /) or q to quit: "); scanf(" %c", &op); if (op == 'q' || op == 'Q') { printf("Program terminated.n"); return 0; } if (op == '+') { result = num1 + num2; break; } else if (op == '-') { result = num1 - num2; break; } else if (op == '*') { result = num1 * num2; break; } else if (op == '/') { if (num2 == 0) { printf("Error: Division by zero is not allowed.n"); } else { result = num1 / num2; break; } } else { printf("Error: Invalid operator.n"); } } printf("Result: %.2lfn", result); } return 0; }